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Re: "writable CTEs"

From: Robert Haas <robertmhaas(at)gmail(dot)com>
To: David Fetter <david(at)fetter(dot)org>
Cc: Peter Geoghegan <peter(dot)geoghegan86(at)gmail(dot)com>, Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov>, marko(dot)tiikkaja(at)cs(dot)helsinki(dot)fi, peter_e(at)gmx(dot)net, pgsql-hackers(at)postgresql(dot)org, Thom Brown <thom(at)linux(dot)com>
Subject: Re: "writable CTEs"
Date: 2010-12-28 12:09:14
Message-ID: AANLkTimHP3Ee6p91FSLWi5+QhTTMQK_dQSb+JfLg3QLG@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-hackers
On Tue, Dec 28, 2010 at 12:45 AM, David Fetter <david(at)fetter(dot)org> wrote:
> I don't see how people can be relying on links to 9.1-to-be's
> documentation.

Well, it's always handy when the filenames are the same across
versions.  Ever looked at the 9.0 documentation for something and then
modified the URL to see what it looked like in 8.1 or something?

>> The main change I've made is: "WITH queries, also referred to as
>> Common table expressions or CTEs, provide a way to write subqueries
>> for use as part of a larger query". I'm concerned that this might
>> not be strictly correct, because the term "WITH query" may not be
>> exactly equivalent to the term "CTE" - WITH queries are comprised of
>> one or more CTEs, plus a main query.  Or are they?
>
> They are. :)

No, actually I think Peter has it right.  A query with one or more
common table expressions is a WITH-query.  This is a subtle difference
but could affect the way that things are phrased in the documentation.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

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